Data comparison in the project

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Basics of project data comparison

Operate

You can compare project data of the same type to identify possible differences. In principle, the following comparison methods are available:

  • Compare offline/online

    With this method of comparison, you can compare the software of the device objects with the project objects. This is only possible once you have established an online connection to the device.

  • Offline/offline comparison

    With this method of comparison, you can compare software or hardware. When comparing software, you can compare objects from projects or libraries. The hardware comparison is available for equipment from a currently open project or from reference projects. For software and hardware comparison, you can decide whether the comparison should take place automatically for all objects or whether you want to compare individual objects manually.

  • Detailed comparison

    For some objects, for example blocks, in addition to offline/online and offline/offline comparisons, a detailed comparison can also be made. This involves opening blocks for side-by-side comparison and highlighting the differences.

A simple offline/online comparison is carried out as soon as an online connection is established. During this process, the comparable objects in the project tree are marked with icons representing the result of the comparison. In the comparison editor, you can also carry out a more comprehensive offline/online and offline/offline comparison. When comparing software, you can also select actions for non-identical objects in the comparison.

Note

  • Not all facilities allow all kinds of comparisons. Which comparison method can be used for which project data depends on the products installed.
  • Compile the user programme before starting the comparison or detailed comparison. After each program change during the comparison, repeat this step before updating the comparison result. This ensures that the comparison shows the current state.
  • When monitoring the module, it is important to note that the difference in time signature can also occur in the case of offline/online comparison if the block is recompiled with a code change. The checksum remains unchanged. In this case, download the block to the device and restart monitoring.
  • In the following cases, the timestamps of objects are used as comparison criteria:
    • Export and re-import via the Openness interface
    • Block calls
    • Access to the global data block (DB)

    This can result in different checksums, even if the objects are identical.

Comparison using checksums

The comparison of offline/online and offline/offline software objects uses checksums generated for specific object data. Objects are only the same if their checksums are identical.

Note

Timestamps are still used for offline/online comparisons for the S7-300/400 series processors.

Facility data falls into two categories:

  • Source data

    Source data is all the data of an object that you have direct influence on, such as the object name, source code, comments or programming language. The properties you can edit here may vary from object to object.

  • Target data

    All compiler and execution environment data are target data. This data may not have a direct impact as it is generated by the system from the source data. Once again, features vary from object to object.

The table below provides an overview of the property comparison areas:

Category

Area

Description

Source data Security Checksum of security objects

Additional information on comparing safety objects can be found in the "Comparing safety programmes" section of the online help for SIMATIC Safety.

Interface without comments Checksum of all first layer block interface tags. Tag comments are not part of the checksum.
Interface of published blocks without comments (programme units) Checksum of all interface checksums of published software entity objects. Comments are not part of the checksum.
Text-based block interface Checksum of all tags, comments and formatting in the text block interface of SCL blocks.
Code without comments Source code checksum. Block and network comments are not included in the checksum. Comments that are not multilingual, for example in STL, and the transfer of free comments to other fields in LAD and FBD, are not included in the checksum.
Comments (multilingual) Checksum of all block and network comments
Language configuration Compare offline/online Displays the languages loaded into the device during the loading process.

Offline/offline comparison: Displays the enabled languages in the project.

Event Checksum of all data relevant to the organisational block (OB) event.
Real Estate Checksum of all configurable object properties.
Extended properties of programme elements in software units Checksum of the publication status of objects in software units.
Configuration of technological facilities Checksum of technology-specific settings of a process facility.
Alarm configuration Checksum of all object settings related to alarms.
Surveillance configuration Checksum of all object surveillance settings.
Text lists Checksum of all text lists of the object.
Tags without comments Checksum of all tags of the selected PLC tag table. The 'Storage' and 'Monitoring' columns and tag comments are not part of the checksum.
Fixed without comments Checksum of all user constants of the selected PLC tag table. System constants and user constant comments are not part of the checksum.
Target data Compilation and execution data Checksum of data for compilation and relevant for loading.
A sign of the times Timestamps for S7-300/400 processors created by the system for compilation and download. Only available if an online connection is available.
Note

  • Note that the object determines which checksums are actually used for comparison.
  • The value settings of the technology objects are also transferred to the block interface checksum.
  • For know-how-protected blocks that were created in an older version, the checksums "Code without comments" and "Comments (multilingual)" are not displayed in "Source data".

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Offline/online comparison

Offline/online comparison allows the device objects to be compared with the project objects.

Requirement

The project tree is open.

Procedure

To carry out an offline/online comparison, follow these steps:

  1. Select a device in the project tree that allows offline/online comparison.
  2. From the shortcut menu, select "Compare > Offline/online".
  3. If you have not yet established an online connection with this device, the "Go online" dialog box will open. In this case, set all the necessary connection parameters and click "Connect".

    The online connection will be established and the comparison editor will open.

Result

All existing online and offline objects are displayed. Symbols in the comparison editor and project tree show the status of objects. In the comparison editor, you can now define specific actions for objects, depending on their status.

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Conducting offline/offline comparisons

With offline/offline comparison, you have the opportunity to compare the project data of two devices. You can carry out software and hardware comparisons. With software comparison, you can compare objects from projects or libraries. The hardware comparison is available for devices from a currently open project or from reference projects. You can decide whether the comparison should take place automatically for all objects or whether you want to compare individual objects manually. The following options are also available for software comparison:

  • For objects that are not identical, actions can be identified to eliminate differences.
  • You can specify the criteria to be used for comparison.

At any time, you can drag any other device into the drop area for further comparisons.

Requirement

The project tree is open.

Performing offline/offline software comparisons

To carry out an offline/offline software comparison, follow these steps:

  1. Select a device in the project tree that allows offline/offline comparison.
  2. From the shortcut menu, select "Compare > Offline/offline".

    The comparison editor opens and the selected device is displayed in the left-hand area.

  3. Drag and drop the additional device into the drop area in the right panel.

    All existing objects of the selected devices will be displayed depending on the settings of the comparison editor in the "Software" tab and an automatic comparison will be carried out. You can identify the status of the objects based on the symbols in the comparison editor. If necessary, specify an action for non-identical objects to eliminate differences.

  4. Define criteria for comparison if necessary.
  5. Select an object to display the details of the property comparison.
  6. If you want to carry out a manual comparison, click the button to toggle between automatic and manual comparison in the status and actions area. Then select the objects you want to compare.

    A comparison of properties is displayed. The status of the objects can be identified from the symbols.

Performing offline/offline equipment comparisons

To perform an offline/offline hardware comparison, follow these steps:

  1. Select a device in the project tree that allows offline/offline comparison.
  2. From the shortcut menu, select "Compare > Offline/offline".

    The comparison editor opens and the selected device is displayed in the left-hand area.

  3. Drag and drop the additional device into the drop area in the right panel.
  4. Open the "Hardware" tab.
  5. If you want to carry out a manual comparison, click the button to toggle between automatic and manual comparison in the status and actions area. Then select the objects you want to compare.

    A comparison of properties is displayed. The status of the objects can be identified from the symbols.

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Author of entries
Tomasz Gilewski

Hello, my name is Tomasz Gilewski. I am the author of books on the S7-1200 controller and HMI panels (i.e. Siemens hardware). I have been programming exclusively on Siemens hardware and engineering tools for several years.

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